Merging 2 Scans With Meshmixer

[kycdental]

Hello, I am having trouble merging 2 scans in Meshmixer to combine it into 1 to pour up a digital impression.

I made the first impression in the patient's mouth and used a lab scanner to scan that impression here:

I then placed this back into the patient's mouth and scanned the palatal side to capture the tray as well as the flabby tissue:

I aligned the 2 scans with my makeshift fiduciary markers to obtain this:

The impressions align pretty well, but I can't for the life of me combine the 2 into 1 single piece (either with combine or with boolean union). Without it being a proper single piece, I can't pour the digital impression to get my master cast. Does anyone have any advice to help me possibly troubleshoot?

Thanks!

 

[Jussi Roivanen]

In meshmixer Booleans are prone to failures, if objects have significantly different mesh density.

Use "make solid" and increase mesh density to 300+ on both objects and then try booleans again.

 

[erzdaemon]

The way i do combining like this is with the bridge tool:

Try to have a very minimal distance between the 2 borders by deleting just a tiny bit of either at the edges.

Then you can use the "Bridge" tool to actually connect both parts ( select multiple very small/thin area on both parts and go edit > bridge ).

in easy words : select tool > 1 small spot on object #1 > 1 small spot on the object #2 > then edit and bridge. This should get you tapelike connections.
Then Clear selection and repeat around the open area.

Try to get many "thin tapes" to connect both objects this way and then use the analyser to close all the remaining holes.

This method can throw some errors though sometimes.

 

[kycdental]

In meshmixer Booleans are prone to failures, if objects have significantly different mesh density.

Use "make solid" and increase mesh density to 300+ on both objects and then try booleans again.

Unfortunately, when I make the scans solid, it "fills" the scans. This won't allow me to properly pour up the impressions later.

 

[kycdental]

The way i do combining like this is with the bridge tool:

Try to have a very minimal distance between the 2 borders by deleting just a tiny bit of either at the edges.

Then you can use the "Bridge" tool to actually connect both parts ( select multiple very small/thin area on both parts and go edit > bridge ).

in easy words : select tool > 1 small spot on object #1 > 1 small spot on the object #2 > then edit and bridge. This should get you tapelike connections.
Then Clear selection and repeat around the open area.

Try to get many "thin tapes" to connect both objects this way and then use the analyser to close all the remaining holes.

This method can throw some errors though sometimes.

I think this would work, and may use this as a last resort. I don't want to manually try and merge them since these are master impressions so I am trying not distort the files as much as possible. Thanks!

 

[Jussi Roivanen]

Unfortunately, when I make the scans solid, it "fills" the scans. This won't allow me to properly pour up the impressions later.

ah. other option is "remesh" and change density (linear subdivision) when doing that. Go into wireframe mode (i dont remember was shortcut key "w" when object is selected),select all nodes (ctrl-a) and "edit > remesh" (shortcut key might be R).

check: https://formlabs.com/blog/meshmixer-tutorial-tips-to-edit-stl-files-for-3d-printing/

 

[kycdental]

ah. other option is "remesh" and change density (linear subdivision) when doing that. Go into wireframe mode (i dont remember was shortcut key "w" when object is selected),select all nodes (ctrl-a) and "edit > remesh" (shortcut key might be R).

check: https://formlabs.com/blog/meshmixer-tutorial-tips-to-edit-stl-files-for-3d-printing/

Tried doing the remesh, but unfortunately this didn't work either. I eventually figured out how to merge them by cutting the palatal surface and then merging the border with the "join" function. It's not a perfect stitch but its better than what I was doing before. I am going to try another technique with the patient when they come back to try and make this a little easier.

 

[Affinity]

Not sure if blender would work better, are the two meshs in the same coordinate system? I mean do they line up when you import them? In blender you would just highlight both meshes and join, then fill holes in the mesh and export as .stl.